Ablation device drive assembly including catheter connector

ABSTRACT

A drive assembly for an ablation device. The drive assembly including a housing and a connector for coupling a catheter assembly including a rotatable drive shaft to the housing. The connector including a first coupling rotatably connected to the housing and a second coupling fixably connected to the housing.

This application is a continuation of U.S. application Ser. No.08/212,319 filed Mar. 14, 1994 now abandoned which is a continuation ofU.S. application Ser. No. 07/960,531 filed Oct. 7, 1992 now abandoned.

BACKGROUND OF THE INVENTION

The present invention generally relates to intravascular devices forablating obstructive material from a patient's vasculature, and morespecifically, to novel improvements in a particular type of occlusionablation devices and improved methods of using those devices.

Several types of intravascular devices are known for ablating occlusionsfrom vascular lumens. The following United States patents discloseteachings relating to a type of such devices that is intended to ablatevascular occlusion material.

    ______________________________________                                        Auth        4,445,509    May 1, 1984                                          Auth        4,646,739    March 3, 1987                                        Auth        4,990,134    February 5, 1991                                     ______________________________________                                    

While these ablation devices function well, there is always room forimprovement. Notably, there are a number of aspects of the ablationdevices as disclosed in the Auth patents, among other occlusion materialablation devices, which are ripe for improvement. Improvements of theprior art ablation devices which address these aspects may increasetheir performance, thereby possibly rendering them more attractive tocertain physicians, clinicians, and other medical professionals forgiven applications.

Specifically, these prior an devices may comprise fixedly joined,unitary drive and catheter assemblies. Because these two assemblies arenot separable, and because the portion of these assemblies that remainsoutside of the patient's body is often bulky, the associated catheterassembly may be cumbersome and sometimes difficult to manipulate. Thebulky nature of these devices may increase the difficulty of catheterinsertion into a patient, tracking the catheter along a medicalguidewire in a patient's vascular lumen, and placement of a distal endof the catheter in appropriate proximity to a stenosis or occlusionwithin the vasculature.

Permanent attachment of the drive assembly and the catheter assembly maydecrease a physician's tactile feel of the movement of the catheterwithin a vascular lumen and along a medical guidewire. The decreasedtactile feel may make it relatively difficult for a medical professionalto properly and efficiently place the catheter assembly within thevascular lumen. The reduced tactile feel and increased handlingdifficulty may make the functionality of these prior art vascularocclusion ablation devices suboptimal. Furthermore, some of theseablation devices may have limited compatibility with currently existingpercutaneous transluminal coronary angioplasty (hereinafter "PTCA")equipment, thereby limiting use of those devices.

During the course of an occlusion ablation procedure, it may bedesirable or necessary to change an abrading or ablating burr toproperly ablate the stenosis, e.g. to change effective ablatingdiameter. Because the drive assembly and the catheter assembly arefixedly connected, the entire catheter assembly must be removed from thepatient and replaced by another catheter to change the dimensions orablating characteristics of the ablating burr. These devices are notreusable and are intended to be disposable, which means that each timean ablating burr is changed, an entirely new device must be employed,thereby possibly significantly increasing the cost of the procedure. Inaddition, because an ablating burr on a given prior art device is notreadily changeable, use of a particular one of these devices may extendthe procedure time.

The construction of the prior art ablation devices allows those devicesto ablate along the entirety of a three hundred and sixty degree arcwithin a vascular lumen as the ablating burr is rotated by a driveshaft. While this degree of ablation may be desirable in somesituations, it may be undesirable in others. Notably, stenosis depositsmay have an eccentric configuration and may not reside along an entirethree hundred and sixty degree portion of an interior surface of alumen. If the prior art ablating burrs are used, thereby ablating alonga three hundred and sixty degree arc along the interior surface of thelumen, some healthy vascular tissue may be ablated along with theocclusive material.

During any intravascular procedure, it is a concern that particulatedebris formed may become embolized. Some of the prior art ablationdevices do not utilize a method of aspiration or other means forremoving the debris from the patient's vascular system. It is believedthat the presence of sufficiently small particulate will not harm thepatient. In theory, the particulate thusly formed is so small as to notform an embolism intravascularly and, therefore, to float freely througha patient's vascular system without adverse effects. However, there isalways room for improvement in the prior art, and it may be desirable incertain circumstances, such as when a large amount of stenosis or lesionis disposed along the vascular lumen interior surface or when the lesionis heavily calcified, to provide some means or method for positivelyremoving the particulate from the patient's vasculature.

Some prior art ablation devices do provide some sort of means forremoving particulate debris generated by operation of the device.However, some constructions of these means can be improved.Specifically, these prior art debris removal means generally comprise alumen in the catheter assembly for applying a vacuum or negativepressure at the distal end of the catheter assembly. This lumen is oftenshared by the drive shaft which conjointly rotates the ablating burr.When vacuum is applied to the catheter drive shaft lumen, the debrisdrawn into the lumen can engage the drive shaft. If sufficient debrisengages the drive shaft, the rotation of the shaft, and thus therotation of the ablating burr, may be limited.

As a vascular occlusion material ablation procedure is performed, thecatheter assembly is progressively axially moved along a guidewire,which often passes through an appropriate lumen in the catheterassembly. Some of the prior art devices have lumens of a configurationwhich limits the types of guidewires that can be used therewith. This isnot desirable as it may limit selection of guidewire types available tothe physician. In addition, the configuration of the catheter guidewirelumen may limit the tractability of the catheter over the guidewire,thereby increasing the difficulty of catheter placement and navigation,within a vascular lumen.

In some instances, the tractability may be so limited that the physicianhas to rotate the guidewire and/or the catheter assembly in order toovercome navigation-inhibiting friction or torque generated between theguidewire and the catheter assembly and/or between the ablating burr orcatheter assembly and a stenosis or lesion. The friction causing thelimited tractability of the catheter assembly may also cause theguidewire or the drive shaft to contort or bend. These contortions cangive rise to spring-like forces within the guidewire and the driveshaft. When the friction or torque causing the contortions of theguidewire and/or the drive shaft cease or decrease sufficiently, theguidewire and/or the drive shaft can "leap forward" within the lumen(i.e. similar to the expansion of a compressed spring). This leapingforward may be increased when the ablating burr progresses through astenosis because a higher magnitude spring-like force may be generated.These spring-like forces may also create a high torsional strain on thedrive shaft, which may inhibit proper operation of the ablating burr.

As the prior art catheter assembly is moved through a patient's vascularsystem, the progress thereof can be monitored by radiography or othersuitable imaging technique. In order to facilitate navigation in thevascular system lumens, a distal end of the guidewire is often providedwith a radiopaque member, usually in the form of a coil or spring,thereby rendering that member visible intravascularly to the relevantmedical professionals. Once the professional properly positions theguidewire with respect to the stenosis, the catheter assembly isadvanced along the guidewire towards the distal end thereof and thestenosis. However, the distal end of the catheter assembly is often notradiopaque. Because the distal end of the catheter assembly is notintravascularly visible to the professional, he must infer theintravascular position of the catheter by "feeling" his way along theguidewire. Because the tactile feel of the catheter assembly may bereduced, as discussed above, precise placement of the distal end of thecatheter assembly with respect to the stenosis may be relativelydifficult as compared to placement of commonly used balloon cathetersproviding the physician with increased tactile feel.

Some of the prior art ablation devices do not allow for retraction ofthe guidewire behind or proximal of the ablating burr. Thus, in orderfor the ablating burr to engage the stenosis to be ablated, theguidewire must be located across the stenosis first. This may berelatively easy in cases where the stenosis extends only from arelatively small angular portion of the interior surface of the lumenand does not amount to a total occlusion of the lumen. However, if thestenosis creates a total occlusion of the lumen, the guidewire may haveto be "punched through" the stenosis to allow the ablating burr toengage the stenosis for ablation or abrasion. Also, similar difficultiesmay be encountered when the vascular dimensions are insufficient toallow an ablating burr to effectively contact a stenosis, such as thatencountered when a portion of a guidewire located distally of theablating burr has dimensions greater than the available vasculardimensions.

When the physician positions the catheter assembly properly with respectto the stenosis, the physician can activate the drive assembly, therebyrotating the drive shaft and the ablating burr in order to ablate thestenosis. In order to adequately ablate vascular occlusion material, therotational speed of the ablating burr should be closely monitored andcontrolled. The prior art ablation devices, however, do not providemeans for easily monitoring the speed of the ablating burr. Furthermore,in some of the prior art devices, ablating burr speed is controlled by afoot pedal actuating a suitable speed regulator. This demands thephysician to coordinate hand, eye, and foot movements in order toperform the relevant procedure.

Some of the ablation devices of the prior art, for example, ablate thestenosis by means of rotational movement of the ablating burr. Whilethis ablating action may be acceptable in some cases, it is not inothers, especially since a stenosis often has an eccentric configurationwithin a vascular lumen. Rotation of the ablating burr can lead toablating along a three hundred and sixty degree arc along a vascularlumen interior surface. Also, rotation of the ablating burr may preventdesired variance of the frequency and amplitude of ablating burr motion,which may be necessary or desirable to ablate a certain stenosis. Also,by simply rotating the ablating burr, the burr may not have sufficientdifferential cutting to distinguish between healthy tissues and diseasedtissues of similar hardness.

In some instances, a physician may determine that, after vascularocclusion material ablation, or other means of intravascular treatment,balloon angioplasty may be required or desirable. This means that, withthe prior art ablation devices, the device must be fully removed fromthe patient's vascular system and replaced by a balloon catheter. Theballoon catheter may be able to utilize the same guidewire as theablation device. But, as noted above, many of the prior ablation deviceshave limited compatibility with other, especially PTCA, equipment.Furthermore, the physician may have to insert and locate a new guidewirebefore he can insert the balloon catheter. These things can furthercomplicate the procedure and also make it more expensive becausemultiple pieces of equipment are used.

The present invention provides a novel vascular occlusion materialablation device. The novel ablation device of the invention offers anumber of improvements over the prior art ablation devices discussedhereinabove, for example, and represents a significant advancement inthe field of intravascular treatments. This novel device and theimprovements to ablation devices are intended to address some, if notall of the above-discussed concerns presented by the prior art ablationdevices. The invention also provides novel, improved methods forvascular occlusion material ablation.

SUMMARY OF THE INVENTION

A general object of the present invention is to provide novelimprovements in vascular occlusion material ablation devices.

A more specific object of the invention is to provide novel improvementsin the ablation devices disclosed in the above-referenced patents toAuth.

Another object of the present invention is to provide a novel ablationdevice which is less bulky and easier to handle than some prior artablation devices.

An additional object of the invention is to provide a novel ablationdevice comprising releasably joinable drive and catheter assemblies.

A further object of the present invention is to provide a novel ablationdevice which gives a medical professional increased tactile feel on anassociated catheter as compared with some of the currently availableablation devices.

Another object of the invention is to provide an ablation device whichfacilitates relatively quick, easy and inexpensive ablating burr changesas compared to some of the prior art devices.

An additional object of the present invention is to provide a novelablation device which can ablate selective portions of a stenosis.

A further object of the invention is to provide an ablation devicehaving greater compatibility with currently available PTCA equipmentthan the prior art ablation devices of the above-referenced Authpatents.

Another object of the present invention is to provide a novel ablationdevice which can remove debris, formed by ablating a stenosis, from avascular system, while insuring that the debris does not interfere withan associated drive shaft.

An additional object of the invention is to provide an ablation devicewhich reduces interference of debris with operation of the device.

A further object of the present invention is to provide a novel ablationdevice which can dilate a lumen.

Another object of the invention is to provide a novel ablation device, adistal end of which is radiopaque.

An additional object of the present invention is to provide a novelablation device including a drive assembly having means for allowing aphysician to relatively easily monitor and control ablating burr speed.

A further object of the invention is to provide an ablation devicehaving increased tractability over a guidewire, as compared to someprior art ablation devices.

A novel ablation device, constructed according to the teachings of thepresent invention, includes releasably joinable, drive and catheterassemblies. The drive assembly includes a tachometer assembly and aregulator for monitoring and controlling ablating burr speed. A dilatingmember is provided in addition to an ablating burr on the catheterassembly. The catheter tube may have multiple independent lumens havingaxes of elongation offset parallelly in the tube. Additionally, theablating burr may be connected to the catheter tube by drive gears orreleasable threads. A radiopaque member is included on the distal end ofthe catheter tube, thereby rendering it intravascularly visible to anobserver. Novel, improved methods of ablating vascular deposits are alsoprovided.

BRIEF DESCRIPTION OF THE DRAWINGS

The organization and manner of the structure and operation of theinvention, together with further objects and advantages thereof, maybest be understood by reference to the following description taken inconnection with the accompanying drawings, wherein like referencenumerals identify like elements in which:

FIG. 1 is a plan view of an improved novel drive assembly, constructedaccording to the teachings of the present invention, releasably joinablewith a separate catheter assembly;

FIG. 2 is a partially sectioned side elevational view of a manifoldassembly comprising a proximal portion of a novel catheter assemblyreleasably joinable to the drive assembly of FIG. 1;

FIG. 3 is an enlarged sectioned side elevational view of a portion of acatheter tube of the invention located distally of a manifold assembly;

FIG. 4 is an enlarged partially sectioned side elevational view of adistal portion of a catheter assembly, illustrating the novelconstruction thereof;

FIG. 5 is a view, similar to that of FIG. 1, of an alternativeembodiment of the novel drive assembly releasably joinable with acatheter assembly;

FIG. 6 is a partially sectioned side elevational view of an alternativeembodiment of a manifold assembly comprising a proximal portion of acatheter assembly releasably joinable to the drive assembly of FIG. 5;

FIG. 7 is an enlarged, partially sectioned side elevational view of adistal portion of a catheter assembly, constructed according to theteachings of the present invention, having an ablating shield therebyallowing the assembly to selectively ablate a predetermined portion of avascular lumen;

FIG. 8 is a fragmentary enlarged elevational view of another embodimentof a distal end of a catheter tube having a threadibly releasablyattached ablation burr;

FIG. 9 is a sectional view, taken along line 9--9 of FIG. 3,illustrating the novel luminal construction of a catheter tube;

FIG. 10 is a view, similar to that of FIG. 9, showing an alternativeembodiment of the novel catheter tube having multiple lumens;

FIG. 11 is a perspective view of an alternative construction of a distalend of the catheter assembly of the invention;

FIG. 12 is an enlarged perspective view of yet another alternativeembodiment of the distal end of the novel catheter assembly, showing aguidewire retracted proximally of an ablating burr, thereby facilitatingoperation of the burr;

FIG. 13 is a partially sectioned side elevational view of a furtherembodiment of the distal end of a novel catheter assembly of the presentinvention; and

FIG. 14 is a partially sectioned end view of a novel guidewire clamputilized in a novel drive assembly of the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

While the invention may be susceptible to embodiment in different forms,there is shown in the drawings, and herein will be described in detail,specific embodiments with the understanding that the present disclosureis to be considered an exemplification of the principles of theinvention, and is not intended to limit the invention to that asillustrated and described herein.

Referring initially to FIG. 1, a novel drive assembly 10 is illustratedwhich is releasably connectable to a novel catheter assembly 12,portions of which are shown in FIGS. 2 through 4, for forming a novellyimproved ablation device. The resulting ablation device is intended tosolve some, if not all of the above-discussed concerns with the priorart ablation devices. Because the drive assembly 10 is separable fromthe catheter assembly 12, a medical professional can have greatercontrol over both assemblies 10 and 12, independently and conjunctively,as will be discussed herein.

The drive assembly 10 comprises a body 14 containing, in the illustratedembodiment, an air turbine, not shown, of known construction forimparting a torque on a drive shaft 16, a portion of which is visibleprojecting from the right hand side of the body 14 as viewed, fordriving an ablating burr 18, shown in FIG. 4, which is operativelyconnected to the drive shaft 16. Other devices for imparting torques tothe drive shaft 16 and the ablating burr 18 can be utilized withoutdeparting from the scope of the invention. The air turbine is driven bycompressed air fed from a compressed air source 20 connected to theturbine by a suitable conduit 22.

The speed of the air turbine, and thus the speed of the drive shaft 16and the ablating burr 18, is determined by the rate of compressed airflow from the compressed air source 20 to the turbine. In order tocontrol the rate of compressed air flow, a flow regulator 24, such as aneedle valve, in the form of a variable orifice valve and the like, isprovided on the conduit 22 between the source 20 and the turbine. In thepreferred construction, the flow regulator can be varied, therebycontrolling the speed of the drive shaft 16 and the ablating burr 18, byhand, and is located proximate to the body 14. In this way, the speed ofthe ablating burr 18 can be relatively easily controlled as compared tosome of the prior art ablation devices. The resulting novel ablationdevice also uses space more efficiently.

In order to provide a physician with an indication of the rotationalspeed of the drive shaft 16 and the ablating burr 18, means in the formof a tachometer assembly 26 is provided on the body 14. The tachometerassembly 26 is operatively connected to the drive shaft 16 by suitablemeans such as by magnets and proximity detectors, for example, andprovides the physician with a visual indication of the speed of theablating burr 18. The tachometer assembly 26 comprises a visual displaywhich may be calibrated to give indications in any desired units, suchas revolutions per minute. Because the tachometer assembly 26 and theflow regulator are both located on or near the body 14, the physicianmay have an easier time in regulating the speed of the ablating burr 18,thereby possibly resulting in a more successful procedure. Thetachometer assembly 26 eliminates the need for optical speed detectorsand the associated, complex fiber optic assemblies. This allows thedrive assembly 10 to make more efficient use of space, as compared tothe devices disclosed in the above-referenced Auth patents.

The drive assembly 10 has further means for assisting the physician inablating a vascular occlusion. A guidewire clamp 28 is attached to thebody 14 for releasably holding a portion of a medical guidewire 45, notshown in FIG. 1, used for guiding the catheter assembly 12 to a stenosisor treatment site within the vascular lumen. The clamp 28 can hold theguidewire 45 with respect to the body 14 so that the drive assembly 10and the guidewire 45 can be moved in unison. The clamp 28 can be appliedto and released from the guidewire 45 by appropriate movement of thephysician's thumb, palm, or finger so that the clamp 28 holds theguidewire 45 at various locations axially along the guidewire 45. Thisaffords the physician greater flexibility during vascular occlusionmaterial ablation procedures, and also facilitates one-handed operationof the device.

The particularly novel construction of the guidewire clamp 28 isillustrated in FIG. 14. Specifically, the guidewire clamp 28 includes aplate 182 which is engageable by a physician's thumb, palm or finger.The plate 182 is pivotally connected to the body 14 by a pivot pin 184such that engagement of the plate 182 causes pivotal movement of theplate 182 about the pivot pin 184. Movement of the plate 182 about thepivot pin 184 allows a portion of the plate 182 to move into and out ofthe body 14 through an aperture 186 in the body 14.

An end of the plate 182 opposite to the end thereof connected to thebody 14 by the pivot pin 184 is pivotally connected to a lever arm 188within the body 14 by a second pivot pin 190. An end of the lever arm188 opposite to the end thereof connected to the plate 182 is pivotallyconnected to a movable contacting arm 192 by a third pivot pin 194. anopposite end of the contacting arms 192 is pivotally connected to afixed contacting arm 196 by a fourth pivot pin 198 such that theguidewire 45 can be clamped between the contacting arms 192 and 196, asshown in FIG. 14. Specifically, the contacting arms 192 and 196 eachinclude radius ed or semicircular portions 200 and 202, respectively,which conjunctively define a diameter slightly smaller than the outerdiameter of a guidewire 45. An end of the contacting arm 196 opposite tothe end thereof including the radius ed portion 202 is fixedly attachedto an interior surface 201 of the body 14 such that the portions 200 and202 are relatively movable between a guidewire 45 engaging position anda guidewire 45 releasing position, shown in FIG. 14, in response tomovement of the thumb plate 182 for releasably clamping the guidewire 45against independent axial shifting.

To facilitate shifting of the portions 200 and 202, a bearing member 204projects from the interior surface 201 of the body 14 adjacent aposition at which the contacting arm 196 is attached to the body 14. Thebearing member 204 projects a predetermined distance towards thepivoting juncture between the lever arm 188 and the contacting arm 192to locate a spring contacting surface 206 on the bearing member 204adjacent a spring contacting surface 208 on the contacting arm 192proximate to the juncture between the lever arm 188 and the contactingarm 192. A spring 210 is disposed between the contacting surfaces 206and 208 such that inward movement of the plate 182 shifts the contactingarms 192 and 196 into the guidewire 45 releasing position, shown in FIG.14, thereby compressing the spring 210. Subsequent relaxation orexpansion of the spring 210 causes the contacting arms 192 and 196 toshift into the guidewire 45 engaging position, thereby substantiallypreventing axial shifting of the guidewire 45. Relaxation of the spring210 also returns the plate 182 to its original, at rest position. It isto be noted that other constructions of the guidewire clamp 28 are alsopossible.

A control knob 30 is provided on the body 14 for axially shifting thedrive shaft 16 with respect to the body 14. The control knob 30 isattached to the drive shaft 16 by suitable means and is shiftable withinan elongate slot 32 in the body 14. In a preferred embodiment, the knob30 is spring loaded and rachet means, or similar structure, may belocated along at least one longitudinal edge of the slot 32 forproviding the physician with an audible indication of shifting of thedrive shaft 16, and/or to increase tactile feel associated with thatshifting as well as providing a locking member for positivelymaintaining axial positioning of the drive shaft 16 relative to the body14.

The knob 30 preferably comprises a thumb lock mechanism for shifting thedrive shaft 16 responsive to movement of a physician's thumb. Thisprovides for one-handed operation of the device and also provides forsmooth movement of the drive shaft 16. Furthermore, the physician canshift the shaft 16 with one simple thumb movement, as compared to theprior an ablation devices where shaft shifting demands two separate,rather complex movements--one to unlock the shaft and one to shift theshaft. Additionally, in the embodiments of the invention, shifting ofthe knob 30 within the slot 32 induces axial shifting of the drive shaft16 with respect to the body 14 and the catheter assembly 12, whenattached. This means that the drive shaft 16 and the ablating burr 18can shift axially independent of the assemblies 10 and 12, therebyleading to greater operational flexibility.

The drive assembly 10 also includes flush and cooling means. The driveassembly 10 is provided with a flushing and cooling fluid, such assaline and the like, from an appropriate fluid supply 34 through asuitable conduit 36. The conduit 36 is connected to valving means, notshown, of known construction within the body 14 which direct the fluidinto a lumen 38, which is visible projecting from the right hand side,as viewed, of the body 14 in FIG. 1. A fluid-tight luer fitting orconnector 40 is provided on the distal end of the lumen 38 forconnecting the lumen 38 to the catheter assembly 12, as will bediscussed further later. The connector 40 is preferably a female luerconnector matable with a complementary male luer connector on thecatheter assembly 12. It is to be noted that, in the illustratedembodiment, the drive shaft 16 is located within the lumen 38, and thatthe lumen 38 and the connector 40 rotate conjointly with the drive shaft16. Accordingly, the connector 40 also functions as means for connectingthe drive shaft 16 of the drive assembly 10 to a drive shaft 42 of thecatheter assembly 12. Also, the lumen 38 can supply cooling and flushingfluid to the catheter assembly 12.

The drive shaft 16 extends axially through the lumen 38 so that thefluid therein can cool the drive shaft 16 and the drive shaft 42 duringoperation.

The drive assembly 10 is releasably connectable to the catheter assembly12 by complementary means disposed on the drive assembly 10 and thecatheter assembly 12. On the drive assembly 10, the means comprises apair of opposing flexible jaws 44A and 44B extending from a side of thebody 14 and flanking the lumen 38. The jaws 44A and 44B are preferablydimensioned such that distal ends thereof terminate short of a proximalend of the connector 40 so that the jaws 44A and 44B can firmly hold theassemblies 10 and 12 together. To facilitate repeatable connection anddisconnection of the assemblies 10 and 12, the jaws 44A and 44B areformed from a material having a sufficient degree of elasticity andelastic memory, such as a plastic and the like. The elasticity of thejaws 44A and 44B insures that the jaws 44A and 44B can separatesufficiently to repeatedly accept passage of a proximal portion of thecatheter assembly 12, while the elastic memory insures that the jaws 44Aand 44B can firmly grasp and retain the catheter assembly 12, even afterrepeated separations.

The proximal portion of the catheter assembly 12 of FIGS. 2 through 4comprises a manifold assembly 52, the function of which will become moreclear later. The jaws 44A and 44B are configured to engage and toreleasably hold an annular flange 46 extending from a proximal end ofthe manifold assembly 52. Specifically, the jaws 44A and 44B includetabs 48A and 48B, respectively, which are releasably interlockablewithin an annular notch 50 on the flange 46. The jaws 44A and 44B arerelatively offset on the body 14 for accepting the flange 46, therebyinsuring a firm connection between the drive assembly 10 and thecatheter assembly 12.

The proximal end of the manifold assembly 52 includes structures forfacilitating releasable operative joinder of the drive assembly 10 tothe catheter assembly 12. Specifically, the manifold assembly 52includes the drive shaft 42, a fluid tight luer fitting or connector 54,and a fluid sealed bearing 56. Also visible in FIG. 2 is a proximal endof a medical guidewire 45, which can extend axially through the driveshafts 16 and 42 and can be proximally releasably held in place by thedamp 28, as discussed above. The drive shaft 42 extends through theentire axial length of the catheter assembly 12, and its proximal endpasses through to the connector 54, while its distal end is connected tothe ablating burr 18.

It is to be noted that the coiled construction of the drive shaft 42shown in FIGS. 3, 4 and 7 is exaggerated for clarity, viz. the driveshaft 42 comprises coils tightly wound such that there are no gapsbetween adjacent coils. The drive shaft 42 preferably includes aguidewire lumen 43 for accepting the guidewire 45 in common fashion inmuch the same way as the drive shaft 16 accepts the guidewire 45. Thedrive shaft 42 is preferably constructed such that the drive shaft 42does not appreciably radially contract upon the guidewire 45 disposedwithin the guidewire lumen 43 during operation of the ablation device10, thereby reducing friction between the drive shaft 42 and theguidewire 45. In addition, the guidewire lumen 43 may be coated with alubricous substance, such as TEFLON® and the like, for reducing frictionbetween the outer diameter surface of the guidewire 45 and the innerdiameter surface of the drive shaft 42. By reducing friction between thedrive shaft 42 and the guidewire 45 disposed within the guidewire lumen43, conjoint rotation of the drive shaft 42 and the guidewire 45 issubstantially limited. This is an improvement over some of the ablationdevices of the prior art having a guidewire that rotates conjointly witha drive shaft during an ablation procedure.

The connector 40 is releasably connectable to the connector 54 so thattorque on the drive shaft 16 can be effectively transmitted to the driveshaft 42, and thus to the ablating burr 18. The connector 54 isreleasably joinable with the connector 40 to also provide a fluid tightconnection between the drive assembly 10 and the catheter assembly 12 sothat cooling and flushing fluid can flow from the drive assembly 10 intoand through the catheter assembly 12. In the illustrated embodiment, theconnector 54 is a male luer fitting releasably insertable into thefemale connector 40. In addition, to insure a secure fit between theconnectors 40 and 54, the connector 40 has internal threads 58engageable with external threads 60 on the connector 54. The threads 58and 60 are oriented such that conjoint rotation of the connectors 40 and54 will not adversely effect the connection therebetween.

A distal end of the connector 54 is fixed to the bearing 56. The bearing56 is dimensioned for insertion into a fluid lumen 62 in the manifoldassembly 52 so that fluid can flow through the connector 54 and thebearing 56 into the lumen 62. The bearing 56 is axially shiftable withinthe lumen 62 to facilitate joinder and separation of the assemblies 10and 12, and provides a proximal, fluid tight seal of the fluid lumen 62.The bearing 56 also rotates conjointly with the connectors 40 and 54 inresponse to rotation of the drive shaft 16. In this manner, fluid in thelumen 62 can flow into the remainder of the catheter assembly 12 duringoperation of the device. It is to be noted that the drive shaft 42extends axially through the bearing 56 and the lumen 62, and through theremainder of the catheter assembly 12 to the ablating burr 18. Thus, themanifold assembly 52 should be able to supply cooling fluid along theaxial length of the drive shaft 42.

In the embodiment illustrated in FIG. 2, the manifold assembly 52comprises a main body 64 and a cap 66 joined to the main body 64 byappropriate means 68, such as an adhesive and the like. The means 68also attaches a catheter tube 70 to the cap 66 for insertion into apatient's vascular system. Therefore, the drive assembly 10 and themanifold assembly 52 are intended to remain outside of the patient'sbody during vascular occlusion material ablation. The cap 66 includes afluid lumen 72 for accepting fluid and the drive shaft 42, and anotherlumen 74, connected to a luer fitting or port 76, accessible from theexterior of the manifold assembly 52, on the cap 66, for supplying thecatheter tube 70 with a drug therapy to be delivered to the treatmentsite, or with positive or negative pressure for a dilating device, suchas a balloon, or for aspiration of the treatment site, respectively. Itis to be noted that, if the treatment site is aspirated, it is desirableto also irrigate the treatment site by a corresponding amount tomaintain the condition of the vasculature. This conjunctive aspirationand irrigation can be achieved, for example, with utilization of thestructure illustrated in FIG. 10, as will be discussed further later.

An alternative embodiment of the releasably attachable drive assemblyand catheter assembly is illustrated in FIGS. 5 and 6. A drive assembly112 is shown in FIG. 5 and a complementary releasably attachablemanifold assembly 114 is shown in FIG. 6. The drive assembly 112 and themanifold assembly 114 are substantially similar to the drive assembly 10and the manifold assembly 52, respectively, except for the differencesto be noted herein, hence the like reference numerals for similarstructures. It is also to be noted that the relevant portions of thecatheter assembly 12 shown in FIGS. 3 and 4 can be used with bothmanifold assemblies 52 and 114.

The drive assembly 112 differs from the drive assembly 10 in that thedrive assembly 112 is not directly connected to a cooling fluid supply34, and therefore, lacks the fluid lumen 38. Cooling fluid is supplieddirectly to the manifold assembly 114. The drive shaft 16 of theassembly 112 is connected to a keyed drive shaft connector 116, which isthe only operative portion of the drive shaft 16 that extends outsidethe body 14. The drive shaft connector 116 forms a positive link betweenthe drive shaft 16 of the drive assembly 112 and the drive shaft 42 ofthe catheter assembly 12 so that torque on the drive shaft 16 can betransmitted to the drive shaft 42.

The construction of the associated manifold assembly 114 is shown inFIG. 6. The assembly 114 comprises a main body 118 joined to a cap 66 byadhesive means 68, however, while the cap 66 on the assembly 114 issubstantially similar to the cap 66 on the assembly 52, the main body118 of the assembly 114 is different from the main body 64 of theassembly 52. Specifically, because the drive assembly 112 lacks aconnection to a cooling fluid supply 34, the main body 118 includes acooling fluid luer fitting or port 120 connectable to a cooling fluidsupply 34 by a suitable conduit 122. The fluid port 120 communicateswith a fluid lumen 124 within the main body 118 for directing coolingfluid from the port 120 to the drive lumen 78 in the catheter tube 70.

Because the drive assembly 112 lacks the connector 40, it is desirableto prevent cooling fluid flow towards the drive assembly 112. In orderto prevent this fluid flow, a fluid-tight seal bearing 126 is providedat an end of the fluid lumen 124 opposite to the end thereof connectedto the drive lumen 78 of the catheter tube 70. The drive shaft 42extends through the bearing 126 for connection to the keyed connector116 on the drive assembly 112. The drive shaft 42 extends through thebearing 126 and the fluid lumen 62 where it is fixedly mounted to arotatable bearing 128, substantially similar to the bearing 56, whichallows fluid to flow into and out of the fluid lumen 62 in the proximalportion of the manifold assembly 114.

A proximal end of the bearing 128 includes suitable means, not shown,which mate with the keyed configuration of the drive shaft connector 116on the drive assembly 112 for insuring joinder of the drive shaft 16 tothe drive shaft 42. To facilitate joinder of the drive shafts 16 and 42,the bearing 128 is axially shiftable within the fluid lumen 62 in themain body 118. The connector 116 and the bearing 128 also allow forpassage of the guidewire 45 therethrough. As noted hereinabove, eachmanifold assembly 52 and 114 can utilize the same catheter tube 70.

The construction of the catheter tube 70 is shown more clearly in FIG.3. The fluid lumen 72 communicates with a corresponding lumen 78 in thecatheter tube 70 for accepting cooling fluid and the drive shaft 42, andthe lumen 74 communicates with another lumen 80 in the catheter tube 70radially offset from the lumen 78. In the embodiment shown in FIG. 2,the means 68 can form a seal on the proximate ends of the lumens 78 and80, which, in conjunction with the particular luminal construction ofthe catheter tube 70 insures complete functional independence of thelumens 78 and 80. Thus, if the lumen 80 were used for aspiration, therewould be no chance that aspirated particles or stenosis debris couldinterfere with operation of the drive shaft 42 within the lumen 78, asopposed to the prior art ablation devices discussed earlier.

Another novel structure, viz. a drive shaft sheath 79, within thecatheter tube 70 is shown in FIGS. 3 and 4. The drive shaft sheath 79overlies an outer diameter surface of the drive shaft 42 and has anaxial length substantially equal to the axial length of the drive shaft42. Specifically, the drive shaft sheath 79 extends from a positionadjacent a distal end of the bearing 56 to a position between the distalend of the catheter tube 70 and a proximal end of the ablating burr 18.The drive shaft sheath 79 substantially seals the drive shaft 42,thereby substantially preventing escape of fluids disposed within thedrive shaft 42, and notably the guidewire lumen 43, from the drive shaft42 and the drive shaft sheath 79. In this manner, irrigation or coolingfluid supplied by the fluid source 34 can flow into the guidewire lumen43 within the drive shaft 42 and axially flow within the space betweenthe drive shaft 42 and the guidewire 45. The drive shaft sheath 79positively retains the fluid between the guidewire 45 and the driveshaft 42 for providing effective cooling of the drive shaft 42 duringoperation of the ablation device 10.

This is a significant improvement over some of the ablation devices ofthe prior art wherein fluid introduced into a lumen between a guidewireand a coiled drive shaft may flow through coils comprising the driveshaft because a gap between an outer diameter surface of the drive shaftand a drive shaft lumen within a catheter tube is larger than acorresponding gap between an outer diameter surface of a guidewire and aguidewire lumen within a drive shaft. The larger gap presents a fluidflow path having less resistance to fluid flow therethrough, therebycausing significant fluid loss from the guidewire lumen, which may leadto inefficient cooling of the drive shaft during operation.

The particular luminal construction of the catheter tube 70 may be moreclearly understood with reference to FIG. 9, which shows a cross sectionof the catheter tube 70. FIG. 9 shows a catheter tube 70 containing aplurality of smaller diameter lumens and elements, viz. the drive shaft42 having a guidewire lumen 43 accepting the guidewire 45, and the fluidor drive shaft lumen 72, which are all substantially concentricallydisposed within the tube 70. However, as noted hereinabove, the lumen 80is offset radially from the lumen 72 and is not disposed concentricallywith the lumen 72, thereby allowing completely independent operation ofthe lumens 72 and 80. Specifically, the lumen 80 has an axis ofelongation radially offset within the tube 70 such that that axis isparallelly offset from an axis of elongation of the lumen 72.

In addition, it is to be noted that, while the lumen 72 has asubstantially circular latitudinal cross section, the lumen 80 has asubstantially elliptical latitudinal cross section. The elliptical crosssection of the lumen 80 allows the lumen 80 to be included within thecatheter tube 70 without having to appreciably expand the outer diameterof the tube 70. Furthermore, as shown in FIG. 10, the elliptical crosssection of the lumen 80 allows for additional, functionally independentlumens, such as the lumen 86, to be disposed within the tube 70 withoutappreciably increasing the outer diameter of the catheter tube 70. Theprovision of these added lumens 80 and 86 gives the physician greaterflexibility during a vascular occlusion material ablation procedure. Forexample, the lumens 80 or 86 can be used to carry a positive or negativepressure fluid from a compressed fluid source 21 to the dilating member82 for inflation thereof. Alternatively, the lumens 80 or 86 can be usedto transport drug therapy or other infusion to a treatment site, or tocarry a negative pressure to the treatment site for the aspirationthereof. In addition, from a manufacturing standpoint, the luminalconstructions illustrated in FIGS. 9 and 10 can be manufacturedrelatively easily, by extrusion methods and the like, as compared to theprior an ablation device catheter assemblies which may require some formof radial support or interconnection among the concentric lumens. Thedistal end of the catheter tube 70 is shown in FIG. 4. The catheter tube70 illustrated includes a dilating member 82 in the form of a balloondeformable or inflatable responsive to pressures in the lumen 80. Inorder to direct positive pressure into the dilating member 82, a plug 84is installed at a distal end of the lumen 80 such that pressures appliedto the lumen 80 from the fluid source 21 are contained therein. The plug84 may comprise a suitable amount of adhesive, an elastomeric member, orsimilar structure and material. The lumen 80 has an aperture 85proximate to the plug 84 and communicating with the interior of themember 82. The aperture 85 allows pressures within the lumen 80 to flowinto the interior of the member 82, thereby inflating or deflating it.While the lumen 80 is illustrated in FIG. 4 as terminating short of thelumen 78, it is to be noted that the lumens 78 and 80 can terminate atthe same axial location.

The member 82 is disposed around the entire circumference of thecatheter tube 70 adjacent the aperture 85, is of known construction, andis intended to allow the medical professional to perform angioplasty orsimilar procedure in conjunction with vascular occlusion material byablation. In addition, by dilating the member 82 sufficiently to engagethe interior surface of a patient's vascular lumen with an outer surfaceof the member 82, the physician can use the contact between the vascularlumen and the dilating member 82 as a fulcrum for applying forces toportions of the catheter tube 70 located distally of the dilating member82. Inflation of the dilating member 82 can center the ablating burr 18relative to a vessel in which the ablation device 10 is inserted andwhich is located proximally of an occlusion to be ablated. The dilatingmember 82 may also prevent the drive shaft 42 and the catheter tube 70from leaping forward in the patient's vasculature. This can provide thephysician with increased navigability of the catheter tube 70, and withincreased options during vascular occlusion material ablationprocedures.

As FIG. 4 shows, an annulus or ring 88 is disposed proximate the distalend of the catheter tube 70, and specifically around the circumferenceof the distal end of the exterior surface of the lumen 78. If the lumens78 and 80 co-terminate, then the ring 88 circumscribes both lumens 78and 80. The ring 88 is formed from a radiopaque material, therebyrendering the distal end of the catheter tube 70 visible to a physicianmonitoring progress of the catheter tube 70 within the patient'svascular system by radiography or similar imaging technique. This is asubstantial improvement over the ablation catheters of the prior artwherein only a distal end of the associated guidewire is radiopaque.

The distal end of the drive shaft 42 extends axially out of the lumen 78and beyond the distal end of the catheter tube 70 where the drive shaft42 is connected to the ablating burr 18 by suitable means. Theconstruction of the ablating burr 18 will be discussed in further detaillater. The ablating burr 18 has a central bore or lumen, not shown, forallowing the guidewire 45 to pass therethrough. The guidewire 45 extendsthrough the ablating burr 18 and terminates at a coil or spring 90. Thesize of the spring in FIG. 4 is exaggerated for rarity, and actually,the spring 90 defines an outer diameter substantially equal to the outerdiameter of the guidewire 45. The spring 90 is usually comprised of aradiopaque material. It is envisioned that many different guidewireconstructions can be utilized with the embodiments of the presentinvention without departing from the intended scope thereof, therebyproviding greater guidewire compatibility.

The specific ablating burr 18 shown in FIG. 4 is but one embodimentthereof, and different constructions can be utilized to achievedifferent ablation results. The ablating burr 18 is a substantiallyellipsoidal body having an abrasive coating 92 disposed over a distalhalf thereof defined by a latitudinal midline of the burr 18. Thisparticular disposition of abrasive 92 allows the ablating burr 18 toablate along a three hundred and sixty degree arc within the vascularlumen responsive to rotation of the drive shaft 42, substantiallysimilar to the ablation or ablating performed by the prior art ablationdevices. This type of ablation may be desirable in certain situationswhere the deposits forming the stenosis are located substantially alonga three hundred and sixty degree arc along the interior surface of thevascular lumen. However, this may not always be the case.

If the stenosis deposits are eccentric, as may often be the case, thephysician may wish to subject a subset of the three hundred and sixtydegree arc on the interior surface of the vascular lumen to the ablationeffects of the ablation device. A novel construction for ablating orablating a subset of a three hundred and sixty degree arc within avascular lumen is illustrated in FIGS. 7 and 11. The construction ofFIG. 7 employs an ablating shield 96 extending from a distal end of thecatheter tube 70. Specifically, the ablating shield 96 extends axiallyfrom the distal end of the catheter tube 70 a distance sufficient tolocate a distal end 98 of the ablating shield 96 forward or distally ofa latitudinal midline of the ablating burr 18. The ablating shield 96also extends substantially radially from the distal end of the cathetertube 70 a distance sufficient to offset the shield 96 radially from theablating burr 18 such that the ablating shield 96 does not interferewith rotation of the burr 18. To further insure that the ablating shield96 does not interfere with rotation of the ablating burr 18, portions ofthe ablating shield 96 adjacent the ablating burr 18 may be coated witha lubricious substance, such as TEFLON® and the like, or may besubjected to a hard coating process such that those portions are notablated by the abrasive 92 on the ablating burr 18. Alternatively, theabrasive 92 can be located on the ablating burr 18 such that portions ofthe ablating burr 18 which can contact an ablating shield 96 do notinclude abrasive 92.

However, the shield 96 can be placed between a periphery of the ablatingburr 18 and a portion of an interior surface of the vascular lumen,thereby shielding that portion from the ablating effects of the ablatingburr 18. By appropriate placement of the ablating shield 96 with respectto the vascular lumen and the ablating burr 18, the relevant portion ofthe vascular lumen will not be exposed to the ablating burr 18.Furthermore, if it is desirable, the ablating burr 18 can be axiallyshifted, as described above, with respect to the catheter tube 70 andthe ablating shield 96 in order to locate the entirety of the abrasivecoating 92 forward or distally of the distal end 98 of the ablatingshield 96, in order to subject a three hundred and sixty degree arc onthe interior surface of the vascular lumen to the ablating effects ofthe burr 18.

The structure of the embodiment of FIG. 11 differs somewhat from thestructure illustrated in FIG. 7. The embodiment of FIG. 11 comprises anablating shield 104 which is essentially an extension of a portion ofthe catheter tube 103. Specifically, the ablating shield 104 comprises atrough-like extension of a less than three hundred and sixty degreearcuate portion of the catheter tube 103 for shielding a correspondingportion of the interior surface of the vascular lumen from abrasion orablation. The angular measure of the are defined by the ablation shield104 may be pre-determined for different applications. The embodiment ofFIG. 11 also utilizes an ablating burr 105 which differs from theablating burr 18 in that the burr 105 does not have an axial boretherethrough to accommodate the guidewire 45.

To account for the lack of the guidewire lumen 43, a separate guidewirelumen 106 is provided on the outer surface of the catheter tube 70 andthe ablation shield 104. The lumen 106 extends from a location adjacentthe distal side of the ring 88 to the distal edge of the ablation shield104. Because the guidewire lumen 106 does not extend along the entireaxial length of the catheter tube 70, the effective length of theguidewire 45 is reduced, viz. the length of the guidewire 45 within theguidewire lumen 106 at any given moment is substantially less than thelength of the guidewire 45 within the guidewire lumen 43. Thus, thecatheter tube 70 of the embodiment of FIG. 11 is relatively moremaneuverable with respect to the guidewire 45, and allows for quickerand easier exchange, as compared to the catheter tube 70 of theembodiments of FIGS. 1 through 10.

In the FIG. 11 embodiment as well, the ablating burr 105 is axiallyshiftable with respect to the catheter tube 70 and the ablation shield104. However, because the guidewire 45 extends beyond the distal end ofthe ablating shield 104, the guidewire 45 may interfere with theoperation of the ablating burr 105 if the ablating burr 105 were shiftedbeyond the distal end of the ablating shield 104. Similar difficultiesmay be encountered with other, similarly constructed guidewire lumensemployed by some prior art ablation devices.

To avoid these difficulties, the invention provides the embodimentillustrated in FIG. 12. This embodiment comprises a catheter tube 108having a drive shaft lumen 78 and a separate guidewire lumen 110 locatedalong a circumference of the lumen 78 such that the lumens 78 and 110are not concentric. The guidewire lumen 110 extends axially through athickness of the catheter tube 108. This allows the ablating burr 105 tobe attached to the distal end of the drive shaft 42 and also allows theablating burr 105 to be axially shifted and operated forward or distallyof the distal end of the catheter tube 108 without interference with theguidewire 45, as distinguished from the embodiment of FIG. 11.

The guidewire 45 can be axially shifted within the guidewire lumen 110among positions proximally and distally of the ablating burr 105. Inoperation, the guidewire 45 can be shifted into an extended positionwith the distal end and spring 90 of the guidewire 45 being in front ofthe distal end of the ablating burr 105 for guiding the ablating burr105 to the intravascular treatment site. Once the treatment site hasbeen reached, the guidewire 45 can be shifted into a retracted position,illustrated in FIG. 12, where the distal end and spring 90 of theguidewire 45 are located behind a proximal end of the ablating burr 105.Thus, the ablating burr 105 may rotate and ablate the stenosissubstantially free from interference with the guidewire 45. This canprovide a treating physician with greater operative flexibility duringvascular occlusion material ablation procedures.

As discussed earlier, it may be desirable to change ablating burrsduring a vascular occlusion material ablation procedure to account forconfiguration variations and morphology of the deposits forming aparticular stenosis. This embodiment of the invention provides novelmeans for changing ablating burrs without having to also change theentire catheter assembly. One such means is the catheter assembly 158illustrated in FIG. 8. This novelly constructed catheter assembly 158comprises an elongate catheter tube 160 intravascularly insertable intoa patient's vasculature. The tube 160 may have a plurality of lumenstherein, and may have a latitudinal cross section similar to those shownin FIGS. 9 and 10.

The catheter tube 160 has at least a drive shaft lumen 162 through whichis disposed a drive shaft 164 for applying force to a novel ablatingburr 166. The drive shaft 164 itself has a unique construction.Specifically, the distal end of the drive shaft 164 includes a portionof the means for changing ablating buns in the form of a socket orconnection member 168, and also has a guidewire lumen 167 for acceptinga guidewire 45. The connection member 168 is fixedly attached to thedistal end of the drive shaft 164 such that the member 168 extendsdistally beyond a radiopaque ring 88 disposed on a distal portion of thetube 160. The connection between the drive shaft 164 and the connectionmember 168 allows for efficient torque transfer from the drive shaft 164to the member 168 so that the shaft 164 and the member 168 rotateconjointly. The illustrated embodiment of the connection member 168 hasthreads 170 thereon for engagement with corresponding threads on theablating bun 166. Other attachment means may also be used. The ablatingbun 166 comprises a substantially ellipsoidal body 172 having anabrasive coating disposed on at least one half thereof. The body 172 hasa guidewire lumen 174 extending axially therethrough for allowingpassage of the guidewire 45, substantially similar to that shown in FIG.4. A proximal end of the body 172 is fixedly attached to another portionof the means for changing ablating burrs in the form of a projection176.

The projection 176 is substantially cylindrical having an enlarged,disk-shaped flange portion 178 for facilitating torque transfer to theablating bun 166 and also to insure firm attachment of the body 172 tothe projection 176. The projection 176 also has threads 180 thereonwhich are releasably threadibly engageable with the threads 170 on themember 168 for forming a firm connection between the drive shaft 164 andthe ablating bun 166. The threads 170 and 180 are configured such thatrotation of the drive shaft 164 and/or the ablating burr 166 will notcause the threads 170 and 180 to become disconnected. A guidewire lumen,not shown in the Figures, also extends through the projection 176 sothat the guidewire 45 can extend through the lumen 167, through themember 168 and the projection 176, and through the ablating burr 166 forintravascularly navigating the catheter assembly 158.

The ablating burr 166 may have different configurations and dimensions,and also the configuration and composition of the abrasive on theablating burr 166 may be different. The connection between the threads170 and 180 insures efficient torque transfer between the drive shaft164 and the ablating burr 166 and allows a physician to quickly changeablating burrs 166 without having to replace the entire catheterassembly. In the preferred embodiment, the member 168 has internalfemale threads 170 and the projection 176 has external male threads 180,and the projection 176 is insertable into the member 168 for engagingthe threads 170 with the threads 180.

Illustrating the construction of this embodiment further by example, thephysician chooses an appropriate ablating burr 166 dependent upon theparticular stenosis to be ablated. The projection 176 on the ablatingburr 166 is inserted into the member 168 such that the threads 180engage the threads 170. The burr 166 is rotated with respect to themember 168, thereby threadibly attaching the burr 166 to the member 168and the drive shaft 164. The physician then inserts the burr 166 and thecatheter tube 160 into the patient and energizes the ablating burr 166to ablate the stenosis or occlusion.

If it becomes desirable to change the ablating burr 166 because of wearon the burr 166, configuration of the stenosis, or the like, thephysician can withdraw the catheter tube 160 from the patient's vascularsystem. Upon withdraw of the distal end thereof from the patient, thephysician can remove the attached ablating burr 166 by application ofsuitable forces, thereby disengaging the threads 170 from the threads180. With the first ablating burr 166 being thusly removed, anotherablating burr 166, possibly having different ablating characteristics,may be attached to the catheter tube 160 by performing the same stepsdescribed hereinabove in reverse order.

Another embodiment of the invention is the catheter assembly 130illustrated in FIG. 13, only the distal portion of which is shown, whichallows for increased maneuverability of the catheter assembly 130 withrespect to a guidewire 45, and for quicker and easier exchange ascompared to the catheter tube 70 of the embodiments of FIGS. 1 through10. It is to be noted that the proximal portion of the catheter assembly130 may be of any suitable construction sufficient to support theillustrated construction of the distal portion. The distal portion ofthe catheter assembly 130 comprises a catheter tube 132 having a driveshaft lumen 134 extending axially therethrough, however, the drive shaftlumen 134 is preferably not located centrally along the axial length ofthe catheter tube 132. This provides clearance for drive means 138 whichrotatably drives an ablating burr 136. The drive shaft lumen 134 alsohas a cooling fluid outlet port 139 proximate a distal end thereof forallowing cooling fluid within the lumen 134 to flow therethrough. Adrive shaft 140 extends axially through the drive shaft lumen 134, andhas a portion of the means 138, specifically a toothed drive gear 142,attached to the distal end of the shaft 140. The drive gear 142 mesheswith a complementary drive gear 144 operatively connected to theablating burr 136 for rotating the ablating burr 136 in response torotation of the drive shaft 140.

The ablating burr 136 includes a shaft 146 projecting substantiallycentrally axially from the burr 136. The shaft 146 extends through asuitable lumen 148 in the distal end of the catheter tube 132. An end ofthe shaft 146 opposite to the end thereof connected to the ablating burr136 is connected to the drive gear 144, which is journally locatedinside the catheter tube 132. The catheter tube 132 has a drive lumen150 extending substantially perpendicular between the drive shaft lumen134 and the lumen 148. The drive lumen 150 is dimensioned for acceptingthe drive means 138, and allows the drive gear 142 to engage the gear144, thereby accomplishing effective torque transfer from the driveshaft 140 to the ablating burr 136.

The catheter tube 132 also has a guidewire lumen 152 which extendsthrough the distal portion of the tube 132 substantially tangentially tothe axis of elongation of the tube 132. The guidewire 45 enters thecatheter tube 132 at an angle sloping towards the axis of elongationthereof, but, because the guidewire lumen 152 terminates at the drivelumen 150, the guidewire 45 can be curved such that the guidewire 45extends substantially parallel to the axis of elongation distally of thedrive lumen 150. The shaft 146 has a through bore 154 which communicateswith a corresponding through bore 156 in the ablating burr 136. Thus,the guidewire 45 can pass through the guidewire lumen 152, through thedrive lumen 150, the bore 154 and the bore 156, and extend beyond thedistal end of the ablating burr 136, as shown in FIG. 13, for guidingthe catheter tube 132 and the ablating burr 136 to the intravasculartreatment site. Because the effective length of the guidewire 45disposed within the catheter tube 132 is reduced, as compared to theembodiments of the invention illustrated in FIGS. 1 through 10, thecatheter tube 132 is relatively more maneuverable with respect to theguidewire 45, and provides for quicker and easier exchanges.

The above-discussed embodiments of the invention provide significantimprovements over the ablation devices of the prior art, andspecifically over the ablation devices disclosed in the above-cited Authpatents. Specifically, by providing an ablation device comprisingreleasably joinable drive and catheter assemblies, the catheter tube ismore delicately and precisely maneuverable or navigable within apatient's vascular lumen. The physician's tactile feel of theprogression of the catheter tube through a vascular lumen is not reducedby connection between the drive assembly and the catheter assembly. Theseparable drive and catheter assemblies also provide for easier, quickerablating burr changes, making it easier for a treating physician toadapt the size of the ablating burr to correspond to the geometry,hardness, and other relevant characteristics of the occlusion to beablated. This may also possibly allow for a reduction of the costs of avascular occlusion material ablation procedure because multipleequipment is not required.

The particularly novel construction of the drive assemblies 10 and 112also allows for substantially one-handed operation thereof, becausecumbersome effects of assembly attachments are reduced, thereby furtherincreasing ease of operation for a physician. Additionally, because thedrive assemblies are releasably attachable to a plurality of catheterassemblies, the embodiments of the invention provide greatercompatibility with other catheter assemblies, as compared to the prioran ablation devices.

The embodiments of the invention also provide a number of ways forrelatively inexpensively changing the ablating characteristics of anablating burr, or for changing the ablating burr itself. The ablatingburrs of the different embodiments can ablate a specific portion of theinterior surface of a vascular lumen. Because the drive assembly and thecatheter assembly are releasably connectable, a different catheterhaving a different ablating burr or ablating shield may be easilyattached to the drive assembly. Also, ablating burrs having threads forthreadibly attachment to a drive shaft may also be provided, therebyallowing change of ablating burrs by simply unscrewing one burr from thedrive shaft and screwing on another ablating burr. Because of thisadaptability, the various embodiments of the invention provide ablationdevices that may have greater indications for use than some prior artablation devices.

The embodiments of the invention also provide novel means for ablatingalong a particular portion of an interior surface of a vascular lumen.By using an ablating shield, a physician can insure that only diseasedtissue is ablated and that healthy tissue is protected. This may beparticularly desirable for ablating eccentric stenosis deposits from alumen. Also, the embodiments of the invention provide a way foreliminating interference with the operation of the ablating burr by theguidewire 45.

Further improvements are presented by the novel debris removal means anda dilating member 82. The debris removal means of the above discussedembodiments prevents debris from interfering with operation of theablating burr, while being relatively easy to manufacture. The debrisremoval means also allows for catheter lumens to be constructed for anddedicated to a particular purpose. The teachings of the construction ofthe debris removal means may also be employed in delivering drugtreatments or other infusions to a treatment site, or pressure from thefluid source 21 to a dilating member 82. The dilating member 82 allows aphysician to perform both occlusion material ablation and occlusionmaterial molding, or angioplasty, or similar procedures, with the samecatheter assembly, thereby possibly further reducing materials necessaryfor the procedures. The dilating member 82 can also be used as afulcrum, thereby providing a physician with increased navigability ofthe catheter assembly within a vascular lumen.

The various embodiments of the present invention also provide greatercompatibility with a plurality of different guidewires 45, especiallyguidewires 45 having a diameter measuring 0.014 inches and 0.018 inches,which tend to be quite popular. The embodiments can be used withguidewires 45 having outer diameters measuring, for example,substantially within the range of 0.01 to 0.02 inches. Thus, a treatingphysician is not limited to a particular guidewire 45 by theconstruction of the ablation device, thereby allowing a physician to usethe guidewire 45 of preference for a particular application, or theguidewire 45 with which the physician has particular skill. This rendersthe ablation devices of the invention more compatible with preexistingPTCA equipment, as opposed to the prior an ablation devices which mayhave limited compatibility.

The greater guidewire 45 compatibility of the embodiments of theinvention also increases the tractability of the device over theguidewire 45, and may increase the physician's tactile feel relating toprofession of the device over the guidewire 45. This greatercompatibility allows a treating physician to use his guidewire ofchoice, which may be important to the physician if, for example, he hasdeveloped substantial skill with a particular guidewire. These thingscan facilitate intravascular navigation of the device over the guidewire45, and may eliminate or reduce the need to rotate the drive shaft withrespect to the device in order to maintain good tractability andpushability.

The novelly improved ablation devices of the invention give the treatingphysician greater visual indicia of operation of the device. The ring88, in addition to the spring 90 often found at the distal end of theguidewire 45, renders the distal end of the associated catheter assemblyradioscopically visible to the treating physician, thereby allowing thephysician to positively locate the device with respect to a stenosis orother vascular obstruction. The embodiments of the invention alsoprovide means to monitor and adjust the speed of an ablating burr withinthe vascular lumen. This means allows the physician to positively setthe speed of movement of the ablating burr. Also, because this means islocated on the drive assembly itself, one-handed operation is stillpossible, and this novel device utilizes space more effectively than theprior art ablation devices.

The embodiments of the invention provide novel improvements in anablation device which can significantly facilitate vascular occlusionmaterial ablation procedures. It is to be clearly understood that whilea plurality of different embodiments of the invention are presentedseparately herein, these embodiments may be included in any desiredcombination on an ablation or other intravascular treatment device.While preferred embodiments of the present invention are shown anddescribed, it is envisioned that those skilled in the art may devisevarious modifications of the present invention without departing fromthe spirit and scope of the appended claims.

We claim:
 1. A drive assembly of an ablation device connectable to acatheter assembly including a rotatable drive shaft, the drive assemblycomprising:a housing; and a connector including a first couplingrotatably connected to the housing about an axis of rotation, the firstcoupling including means for releasably connecting the drive shaft tothe housing for rotating the drive shaft relative to the housing, andthe first coupling including a fluid tight seal to allow fluid to flowbetween the housing and the catheter assembly; and the connectorincluding a second coupling fixedly connected to the housing andincluding means for releasably connecting a portion of the catheterassembly to the housing, the second coupling retaining the portion ofthe catheter assembly from rotation relative to the housing while thefirst coupling rotates with the drive shaft.
 2. A connector inaccordance with claim 1, wherein the first coupling is slidablyconnected to the housing to allow the position of the first coupling tobe shifted along the axis of rotation.
 3. A connector in accordance withclaim 1, wherein the first coupling includes an internally threadedconnector capable of threadably connecting the drive shaft to thehousing.
 4. A connector in accordance with claim 1, wherein the secondcoupling includes two generally opposing flexible jaws extending fromthe housing.
 5. A connector in accordance with claim 4, wherein each jawincludes a tab engagable with the catheter assembly to connect theportion of the catheter assembly to the housing.
 6. A connector inaccordance with claim 5, wherein the jaws are formed at least in partfrom a resilient plastic.